This invention relates to a flow control system and more particularly relates to the automatic shut off of one fluid when another fluid falls below a predetermined pressure.
In the manufacture of articles in which plural components are simultaneously mixed and sprayed on the article it is imperative that the ratio between the two fluids be maintained. In plural component systems the critical component is the catalyst which is carefully controlled in order to assure the proper mixture and curing of the resin. If the catalyst flow falls below a desired amount the mixture is effective causing the manufacture of defective parts. The catalyst and resin supply systems are controlled by pneumatically operated devices. Gauges are provided but the operator of the spraying equipment is not always aware of the actual pressure. In some cases he may manufacture several parts before he realizes the mixture is defective. This can result in not only a waste of considerable material but defective parts which are unusable. In some cases the mixture may only be slightly below the required amount and the defective parts may be distributed without realizing that there was an improper mixture. This can result in extra cost for the defective part, because of the necessity of utilizing longer cure times in order to correct the defect as well as the potential complete waste of completely defective parts which cannot be corrected.